physiology renal 1 Flashcards
function of kidney
- maintain h20 and salt balance in body
- maintain acid-base balance in the body
- maintain plasma volume
- Excreting the end products (wastes) of bodily metabolism and drug metabolites
- Producing erythropoietin (rbc formation)
- Producing renin
Structures that carry urine from the kidneys to the outside for elimination
from the body
- Ureters
- Urinary bladder
- Urethra
Ureters:
structure
exits each kidney..
function
- smooth muscle walled duct
- at the medial border, close to the renal art&vein
- carries urine to urinary bladder
urinary bladder
structure
function
hollow smooth muscle
Temporarily stores urine
Urethra function structure in females structure in males
- transports urine to out of the body
- short and straight
- much longer and follows a curving course …… Dual function: the elimination of urine from the bladder AND passageway of semen from reproductive organ
The functional unit of the kidney:
THE NEPHRON
~1 million nephrons per kidney
- Each nephron has two components:
2. Arrangement of nephrons within kidney gives rise to two distinct regions:
Vascular component and tubular component
Outer region: the renal cortex
Inner region: the renal medulla
glomerulus
function
filtering component of kidney
water and salts are filtered
glomerulus
blood. pt1
from renal artery blood passes afferent arterioles which deliver blood to glomerulus
efferent transport blood from glomerulus
glomerulus
blood pt2
efferent arterioles break down into peritubular capillaries which surrounds the tubular part of nephron
peritubular cap join into venules which transport blood to. the renal vein
Water and solutes are filtered through glomerulus as blood passes
through it
Tubular component of nephron
hollow, fluid filled tube made up of single layer epithelial cells
Tubular components
bowmans capsule proximal tubule loop of henle (descending. and asc. limb) Juxtaglomerular apparatus distal tubule collecting duct
- Two types of nephrons
- defined by
- juxtamedullary and cortical nephrons
- length and location
Basic renal processes (Glomerular filtration)
fluid filtered from glomerulus into bowmans capsule pass thru 3 layers of membrane:
- glomerular capillary wall
- basement membrane
- inner layer of bowmans capsule
Glomerular capillary wall
single layer of endothelial cells
more permeable to water and solutes than capillaries else where in body
Basement membrane
Acellular gelatinous layer
composed of collagen and gylcoproteins
Inner layer of Bowman’s capsule
consists of podocytes that encircle the glomerulus tuft
The glomerular filtration rate (GFR) is about
125 ml/min in a normal adult
Glomerular Filtration:
Ultrafiltrate
cell and protein free
conc. of small solutes is the same as plasma
a condition called proteinuria
in some diseases the - charge is on the filteration barrier is lost and so the proteins are more readily filtered
Net filtration pressure =
The volume of plasma filtered through the glomerular capillaries into Bowman’s capsule per unit time
Forces involved in glomerular filtration
if they favour or oppose filteration
–Glomerular capillary bp F
–Plasma-colloid osmotic pressure O
–Bowman’s capsule hydrostatic pressure O
Renal blood flow (RBF)
- what % rbf is from cardiac output
- determines
- autoregulated between
- 25
- GFR
- 90 – 180 mmHg
filteration is driven by
starlings forces across walls of glomerular caps
